This disclosure relates to a multichip package, methods of manufacture thereof and articles comprising the same.
Multichip packages often contain chips, integrated circuits and similar components. They often include optical transceivers enabled to communicate with devices that lie outside of the multichip package. Laser diodes, used in these optical transceivers are small and compact, they are efficient at converting electrical energy into laser energy, and they are reliable. However, when a laser diode is operated at a high average power, it generates a substantial amount of heat in a small volume, thereby raising the temperature of the multichip package, which causes negative effects such as a wavelength shift and a loss of efficiency and reliability. If the temperature gets high enough, destruction of the multichip package may result. Multichip packages having semiconductor laser diodes are therefore often placed in communication with heat exchangers in a separate package from other electronic components.
For example, in order to achieve maximum efficiency, it is desirable for a multichip package that employs chips, integrated circuits and/or optoelectronics to operate at a temperature that is below 60° C. For reliable, long-lived operation, operating temperatures of less than 85° C. facilitate operation of the multichip package without a substantial loss of efficiency. Temperatures even moderately above 85° C. will substantially affect efficiency and reliability, substantially shortening the useful life of the multichip package. Furthermore, at these higher temperatures the output laser light will be shifted in wavelength. High temperatures encourage the growth and propagation of defects in semiconductor lasers, which decrease their efficiency (light output produced for a given amount of input electrical current). A larger current may be applied to compensate for the decreased efficiency, which then produces even more heat, encouraging the growth of even more defects and a greater loss of efficiency. If such multichip packages are maintained at or near their optimum temperature, then the chips and/or diodes disposed thereon will perform at maximum efficiency for a large lifetime, and emit a consistent wavelength.
It is therefore desirable to have a multichip package that can be cooled sufficiently to produce a high average power. It is also desirable for the cooling system to be designed so that fiber optic cables communicating with the laser diodes will not be damaged. In addition, it is desirable for the multichip package and the cooling system to be designed so that a high flow rate of coolant can be achieved.